环虫酰肼的合成

Synthetic Process of Novel Pesticide Chromafenozide

乙酰乙酸乙酯与甲醛缩合,然后脱羧得到2-甲基-4-氧-2-环己烯甲酸乙酯,在四乙基溴化铵催化下与1-溴-3-氯丙烷反应,得到5-甲基-7,8-2H-6-苯并二氢吡喃甲酸乙酯,再在硫粉的催化下脱氢得到5-甲基苯并二氢吡喃-6-甲酸乙酯,然后经水解、酰肼化得到关键中间体N-5-甲基苯并二氢吡喃-6-甲酰-N'-特丁基肼,最后与3,5-二甲基苯甲酰氯反应得到环虫酰肼,总收率23.3%。

Ethyl 2-methyl-4-oxo-2-cyclohexen carboxylate was synthesized using ethyl acetoacetate and formaldehyde as the primary materials, and then ethyl 7,g-dihydro-5-methylchroman-6-carboxylate was prepared by the reaction of ethyl 2-methyl-4-oxo-2-cyelohexen carboxylate and 1-bromo-3-chloro-propane in the presence of Et4NBr as catalyst. Then, ethyl 7,8-dihydro-5-methylchroman-6-earboxylate was dehydrogenated with sulfur and hydrolyzed to give ethyl 5-methyl-ehroman-6-earboxylic acid. Ethyl 5-methylchroman-6-carboxylic acid reacted with H2NNHBu-t to give N-5-methyl-1,4-benzodioxan-6-carbo-N＇-tert-butylhydrazine which was the important intermediate of chromafenozide. Then chromafenozide was obtained by the reaction of the N-5-methyl-1,4-benzodioxan-6-earbo-N＇-tert-butylhydrazine with 3,5-dimethlybenzolyl chloride. The total yield was 23.3%.